Process and apparatus for carrying out reactions by the action of electrical glow discharges



June 3, 1958 B BERGHAUS ETA 2 837 654 PROCESS AND APPARATUS FOR CARRYINGLOUT REAcTIofis BY THE ACTION OF ELECTRICAL GLOW DISCHARGES Flled. May 9, 1955 2 SheetsSheet 1 IIIIIIIIIIIA IIIIIIIIIIIA fllllllllllllf VIII/Ml?? INVENTORS BERNHARD BERGHAUS AND HANS BUCEK ATTORNEY June 3., 1958 a. BERGHAUS ETAL 2,837,654

PROCESS AND APPARATUS FOR CARRYING OUT REACTIONS BY THE ACTION OF ELECTRICAL v GLOW mscmacss Filed May 9, 1955 2 Sheets-Sheet'Z INVENTOIU BERNHARD BERGHAUS AND HANS BUCEK I ATTORNEY PROCESS AND APPARATEJS FOR CARRYING OUT REACTIONS BY THE ACHON 9F ELECTRICAL GLOW DISCHARGES Bernhard Berghaus and Hans Bucek, Znrich,,Switzerland, assignors to Eiektrophysikalische Anstalt Bernhard Berghaus, Vaduz, Liechtenstein Application May 9, 1955, Serial No. 506,752

Claims priority, application Switzerland May 11, 195 4 18 Claims. ((31. 25ti49.5)

This invention relates to a process and apparatus for carrying out reactions on gaseous, vapourous, or finely dispersed substances, under the action of electrical glow discharges in a reaction receptacle provided with electrodes, at least one supply device for the starting substances, and at least one gas suction device.

Various processes and apparatus of this kind are already known, in which a glow discharge is produced in a suitable receptacle between electrodes to which a volt-- age is applied, which glow discharge acts upon a gas current and produces reactions therein. In the known processes of this kind, the electric field acts eitherthrough layers of insulation, whereby the pressure in the reaction vessel may then be chosen as desired, but in which, for thermal reasons, the glow discharge, which is mostly produced on the surfaces of the insulating layers, cannot be increased beyond relatively low values. On the other hand, in the case of discharge receptacles in which the electrodes to which the voltage is applied lies freely opposite one another, the glow dischargewhichis produced follows the known laws, according to which an increase in the energy of the glow discharge necessarily produces a pressure increase in the discharge receptacle, which, in its turn, results in a gradual concentration of the energetic discharge upon the glow covering the parts to which a voltage is applied. Although the energy transformation can thus be greatly increased with increase in pressureif the glow discharge is prevented from passing into an arc dischargethe energy is freed only in the immediate surrounding of material surfaces. When the reactions are carried out in connection with gaseous, vapourous, or finely dispersed substances, the

presence of such surfaces participating in the process are frequently undesirable; however, energetic glow discharges were not known hitherto to take place in the free space between the electrodes.

The object of the present invention is to produce such a glow discharge and it relates to a process for carrying out reactions on gaseous, vapourous or finely dispersed substances by the action of electrical glow discharges in a reaction receptacle with electrodes, at least one gas suction connection and at least a device for the supply of material to be treated. The characteristic feature thereof is that a non-homogeneous distribution of pressure is produced inside the receptacle, whereby a predetermined zone of high pressure is produced, within which up to 90% of the pressure drop is localised. The energy of the electrical gas discharge is largely concentrated in this zone. The starting substances flow through this zone and can reach into the zone of lower pressure only along this path, whereby the supplied substances remain in the said zone for a predetermined time.

The invention also relates to an apparatus for carrying out this process consisting of a reaction receptacle with at least one insulated electrode introduced therein, at least one connection for the supply of gas into the receptacle and at least one gas outlet connection. The characteristic feature thereof is that it comprises at least which'opens into the interior of the receptacle in such 2 r i one supply member with at least one nozzle-like opening,

a manner that a gas current leaving the nozzle-like opening is present at least in the proximity of the opening, in the effective region of an electric field between electrodes carrying voltage. A further characteristic consists in at least. one outlet member connected with a pump and providing a predetermined reduced pressure at least in the region of the inner space of thereaction receptacle which is adjacent thereto.

It is necessary toexplain more clearly the expression technical problems require an introduction of gases into such spaces of reduced pressure, for instance in the case of treatment of work-pieces in a receptacle under the action of a glow discharge, it being known to use in some cases bored or perforated electrodes, but this always occurs by taking into consideration and making use of the fact that a uniform pressure distribution prevails inside the receptacle. a

It is known in other domains of theart and from the theory of flowing gases (Prandtl) to use gas currents the velocity of which are of the order of the speed of sound. As an example on a larger scale one may mention the operation of jet nozzles, for instance at reduced pressure (stratosphere). I

On the face of it, it appears diflicult to produce zones of high pressure within a receptacle for electrical gas discharges and to maintain them operatively. As-a .dynarnical problem, this task can be easily solved as regards the reduced pressures that come into question and can be adapted to the factors that are interesting from a practical point of View with respect to the amount of flow, the speed of gas, the kind of gas, etc. As an example one may mention that a current of gas which flows out of a nozzle of 1 mm. diameter into a discharge receptacle with a reduced pressure that is normal in the art of gas discharges of about 5 mm. Hg, requires for the maintenance of this reduced pressure a pump power of about 400 litres per minute, which canbe easily attained with the technical means that are nowadays ava.il'

able.

Thus, it is possible, by applying the technical rule according to this invention, to produce-in a gas discharge receptacle with comfortable technical expenditure such zones of increased pressure and therewith a non-homogeneous distribution of pressure, to maintain it operatively for any desired period of time, as well as for carrying out technical processes by the action of strong electrical discharge produced by the glow discharge. I

Various examples for carrying out the invention are hereinafter described with reference to Figures 1 to 9 of the accompanying drawings, wherein:

Figure l is a diagrammatic representation of the principle of a discharge receptacle for carrying out the process;

Figures 2 and 3 show partly in longitudinal section a supply member to the reaction receptacle;

Figures 4 to 8 show respectively a further embodiment of a reaction receptacle suitable for carrying out the presout process; and a Figure 9 is a diagram of the progress of the pressure and a general diagram of one example of construction of the apparatus for carrying out the process.

Figure 1 shows one example of construction of a re- Patented June 3, 1958 action vessel 1 made of insulating material or of metal for producing a discharge according to the present process. A supply member 2 madefor instance of metal and provided with an elongated nozzle-like opening 3 is introduced in an insulated manner into the vessel 1. A gas suction member 4, indicated simply as a small connecting pipe, is connected to a suitable'pumping device (not shown) so that .a desired reduced, pressure can be produced in the interior of the receptacle. metal supply member 2, which is connected through the connection 5 with one pole of a source of voltage (not shown) a counter-electrode 6 is mounted in the receptacle 1, the same being introduced in an insulated manner through the wall of the receptacle and connected throughfthe connector 7 to the other pole of the said source of voltage.

An essential feature according to the present process is that within the discharge receptacle 1 there is produce a non-homogeneous pressure distribution, and there- 'by a zone of increased pressure. A predetermined reduced pressure P (Fig. 9) is maintained in the reaction receptacle 1 by the suction member 4-, whilst providing for an adequate pump power by the pumping device that is connected up, at least in the immediate surrounding of the openingof the suction member, and at the same time a current of gas is introduced through the nozzle-like opening 3 of the supply member. By suitably adjusting the pressure P at the mouth of the nozzle 3, its inner diameter and the pump output at the suction member 4, a stationary condition is produced in which, accordingly, the pressure difference (P -P is maintained in the reaction receptacle between the mouth of the nozzle 3 and that of the suction member 4!. As it is known from the theory of a current of gas flowing from a nozzle into a space of reduced pressure, a zone is formed near the mouth of the nozzle 3 in which the pressure drops quickly in all directions, whereby, according to the shape of the nozzle, surfaces of the same pressure within this zone may assume difl erent shapes. Such isobars 8a, 8b, 8c are illustrated diagrammatically in Figure l for a zone of increased pressure rotationally symmetrical with respect to the axis of the nozzle, whereby however, the radial extension of the spindle-like shaped surfaces of equal pressure are shown, for the sake of clearness, on a larger scale compared with the actual shape. Moreover, for the same reason, the deformations of increased pressure occuring mostly directly next to the mouth are not shown.

If the current of gas broadens in the inner space of the reaction receptacle 1, which is held at a constant reduced pressure P without any obstruction, that is to say, if the probe 9 has no influence, then the surfaces of equal pressure, surrounding each other at equal pressure difierence between successive surfaces, will not cut, for instance, the axis of the current, each time at equal distances. Moreover, an extensive concentration of the major part of the whole pressure drop (Pg-P1) takes place within a comparatively limited zone adjacent to the nozzle mouth, which comprises for instance up to 90% of the pressure drop. Owing to this peculiarity of the zone of increased pressure the influence of the size of the receptacle, and of the zone enclosing the same with a reduced pressure of approximately P is very small, since at this point only a small portion of the pressure drop (Pg-P1), for instance altogether 10% is localised.

If a glow discharge is produced between the leading-in member 2 as cathode and the counter-electrode 6 as anode, as long as the whole of the inner space shows everywhere a reduced pressure P and no gas enters through the nozzle 3, the known glow phenomenon is produced, in which, depending upon the pressure P the energy of the discharge is more or less completely freed in the layer of glow covering the cathode. However, these conditions are immediately basically changed, as soon as a current of gas enters into the reaction receptacle 1 through the nozzle 3, even when, by a suitable increase in the Opposite the between the strong discharge within the zone of increased pressure and its surroundings. By a suitable choice of the reduced pressure P in the surrounding of the mouth of the suction member 4 and in the region outside the zone of increased pressure, on the one hand, and the pressure P of the inflowing gas at the mouth of the nczzle 3, on the other hand, the supply of energy for the discharge over the electrodes 2 and 6 can be increased to a value which causes, at least in the parts of the zone of increased pressure a light emitting discharge phenomenon.

This luminous phenomenon within the zone of increased pressure is developed from the usual glow discharge at the cathode but, as a luminous zone free in the gas space, it is structurally diflferent from all the glow discharge phenomena hitherto known in the gas space. The appearance and the shapeof the luminous zone is approximately determined by the surfaces 8a to 8c of the zone of increased pressure, but it is only occassionally seen as a layer within the luminous appearance. The spectrum scale of the emission of light is mainly determined by the reactions Which take place in the zone of increased pressure. The light emitting areas within the zone of increased pressure are not the only ones that come into question for the present purpose, namely, for carrying out reactions; the actual reaction zone rather extends over the whole zone of increased pressure and its direct surrounding. The zone which is in the neighbourhood of the nozzle wherein up to about of the whole pressure drop is localised is, as already mentioned, the zone of increased pressure.

The shape of the reaction zone depends to a large extent on the spacial shape of the surfaces 8 which areof equal pressure, although the reaction zone need not be identical therewith. An essential feature of this form of the discharge consists, however, in the sharp delineation of the zone of high energy transformation with respect to its surrounding with low energy transformation. This property of the reaction zone produced by the process according to the invention, which zone is very advantageous when carrying out reacti0nsas will hereinafter be describeddepends, on the one hand, on the exponential curve of the pressure drop from the interior to the edge of the zone of increased pressure and, on the other hand, on the known law concerning the dependence of the energy of gas discharges upon pressure, according to which, the energy transformation increases with approximately the third power as a function of the gas pressure.

' The spacial shape of the surfaces 8 of equal pressure depends to a large extent upon the shape of the nozzle 3 and its mouth, as well as upon the speed of the outflow of the gas current from the opening of the nozzle, viz., from the total pressure difference (P -P Within the reaction receptacle. If a high concentration of energy is desired, and therefore a small Volume of the reaction zone, it is advisable to introduce a thread-like gas jet into the reaction receptacle. If, on the other hand, a reaction zone of larger dimensions is wanted, the same may be produced by means of a comically shaped gas jet. In one case, the nozzle 3 is constructed as a cylindrical elongated bore in the supply member 2, and in the other case the supply men. er 2 is provided, either with a rose-like head with a plurality of individual bores having different spacial directions, or with only one nozzle with conical formation of the jet outlet.

Since in the case of pressure conditions and nozzle dimensions .which are of interest for practical applications, the gas current leaves the mouth of the nozzle with a speed which is of the order of the speed of sound, and even a multiple thereof, at times, pressure zones of other shapes are also formed.

The gas current entering the reaction receptacle forms freely and unobstructed a generally elongated zone of increased pressure next to the mouth of the nozzle 3, which abuts all round against the surroundings of reduced pressure. In the case of such a zone of increased pressure, for instance as shown in Figure 1 by the isobars 8a, 8b, 8c, a particle moving along the axis of the jet stays naturally a longer period of time within the zone of increased pressure than a particle following a curved path, and leaves the zone of increased pressure already in the proximity of the mouth. If this is not desired, it is possible to influence the shape of the zone of increased pressure as well as the period of staying in the gas current and its parts by means of adjacent solid walls. For instance, by using such walls an elongated channel may be formed through which the gas flows. The channel may be of any desired section.

One example of construction of a supply member 2 with a cylindrical bore serving as a nozzle 3, and a cylindrical continuation 10 for producing the zone of increased pressure, is diagrammatically illustrated in Figure 2. If desired, walls in the shape of baffle plates may also be provided, by means of which the gas current is deflected, as is shown in Figure 3, in which a baffle member 12 is arranged opposite the head 11 of the supply member 2 in the form of a rose.

In a reaction receptacle of the kind shown in Figure 1, a reduced pressure P mm. Hg Was, for instance, maintained with a suction output of about 400 litres per minute and a gas current was led through a cylindrical nozzle of about 1 mm. diameter into the reaction receptacle. At the mouth of the nozzle in the reaction receptacle there prevailed a pressure of about P =0.5 kg./cm. and an inlet speed of the current of the order of 500 m./sec. In these conditions there is obtained a luminous region within the zone of increased pressure about 80 mm. long with a diameter of 2 mm. However, it is possible to maintain also a much' lower reduced pressure P if the suction output of the pumping de vice is adequate therefor, and a concentration of the discharge in the zone of increased pressure was obtained for a short period of time at a pressure P of approximately 0.01 mm. Hg. On the other hand, also in the case of an internal pressure of a reaction receptacle it is possible to produce a zone of increased pressure up to 1000 mm. Hg and a correspondingly greater increased pressure P of the incoming gas current which, it is true, is of substantially smaller spacial dimensions, but likewise shows a concentration of energy of the discharge in this zone, producing a luminous appearance, which cearly diifers from the very thin layer of glow, present under such pressure conditions in the supply member serving as cathode. A pressure P in the range from 0.4 to 40 mm. Hg was found to be especially suitable for carrying out reactions within the zone of increased pressure.

The spacial delineation of the zone of increased pressure and discharge phenomena of great energy with respect to the surroundings in which the energy transformation is substantially lower, in most cases negligible, is sharper the greater the total pressure drop P :P In this case, values of over 1:50 can be reached with medium pump output and nozzle dimensions that can be produced without difficulty. This sharp delineation of the zone of higher pressure prevents, also in the case of a large energy transformation, a transition of the electrical discharge in the reaction receptacle into an arc discharge between electrodes to which a voltage has been applied. However, a reliable operation with a substantial concentration of energy in the zone of increased pressure is also possible with a pressure drop of at least 1:2. Also the speed of the gas current at the outlet of the mouth of the nozzle is dependent upon the pressure drop P :P This current speed ought to be at least one-tenth of the speed of sound but, with a sufficiently reduced pressure P and great pressure drop P :P it may increase up to a multiple of the speed of sound. The choice of the speed of the current depends upon the time desired for the current to remain within the reaction zone.

In order to obtain the desired electric discharge and concentration of the transformation of energy thereof in the zone of increased pressure, this zone must be produced in a region of the" reaction vessel which is at least partly under the action of an electric field. This field is preferably obtained by means of a direct current voltage between suitable electrodes, whereby an action of the reaction zone is obtained which is temporarily constant. However, the process is not limited thereto, but may be carried out by using a voltage of constant polarity which is not temporarily constant or by using an alternating current voltage.

In an arrangement as shown in Figure 1 of the accompanying drawings, in which the supply member 2 with one or more nozzles 3, made of metal, is connected through the terminal 5 to one pole of a source of voltage, thus forming an electrode which lies opposite a counterelectrode that is connected to the other pole of the source of voltage through the terminal 7, the axis of the nozzle runs approximately parallel to the direction of the electric field between the electrodes 2 and 6 and the gas flows approximately parallel to the direction of the field in the reaction receptacle. However, also the reaction receptacle. 1 may serve as a counter-electrode when it is made of metal, the gas current entering therein in a direction transverse to that of the field. With a suitable arrangement of electrodes 13 and 14 within a reaction receptacle 1, as shown for instance in Figure 4, the current of gas may flow from the nozzle 3 of the supply member 2 into the receptacle at right angles to the direction of the field, which, in this case, is produced between the electrodes 13 and 14. The two electrodes are connected througn the terminal 15 and 16 with the poles of a direct or alternating source of voltage, whilst the supply member 2 has no electrical connection with the supply circuits. The supply member 2 may, in this case, consist wholly or partly of electrically insulating material or of a metal member connected with the reaction receptacle 1. If the supply member 2 is of metal and mounted in an insulated manner in the reaction receptacle 1, the same may be connected through a terminal 5 with the middle conductor of a two-phase alternating current supply, the two phases of which feed the electrodes 13 and 14 by their respective connections to the terminals 15 and 16.

The distance between the electrodes, viz. 6 in Figure l, and 13 and 14 in Figure 2, in the zone of increased pressure formed next to the nozzle openings, is not of much importance as regards the energy concentration within this zone. One has merely to prevent the occurrence of an arc discharge between the electrodes to which a voltage is applied. Under these conditions of operation, in which it is possible to obtain a sharp delineation of the zone of increased pressure with respect to the surronndings, the distance can be reduced to such an extent that the electrodes abut directly against the discharge zone of high concentration of energy.

In the example shownin Figure 5, the reaction receptacle consists, for example, of a container 17 of insulating 1 material and a metal cover 18, which forms an electrode and is connected with the terminal 19 to the one pole of a source of current. In the proximity of the supply member 2 there is provided a second electrode 20 which, in this case, is constructed, for instance, as acoaxial metal ring which is connected through the terminal 21 to the other pole of the source of voltage. member 2 may be of insulating material and requires The supply no conducting connection with the source of voltage. If desired, also the supply member 2 may be made of metal and be connected through its terminal with the terminal 19 in parallel.

The solid walls serving to produce the shape of the zone of increased pressure, which wall may be arranged as already mentioned in the immediate proximity of the opening of the nozzle, may also be made wholly or partly of metal and be used as electrodes. Likewise, a baffie plate, for instance 12 as shown in Figure 3, may serve as an electrode, if it is made, at least partly, of metal. Finally, it is to be pointed out that the electrodes, in so far as they are not used at the same time as supply members, may be constructed to serve as suction members, for instance as is indicated in section in connection with the electrode 14 in Figure 4. Bafi'les and other walls may also be so arranged that they can be used for suction.

Figures 1, 4 and 5 show only one supply member 2. As compared therewith, Figure 6 shows a reaction receptacle 1 with two supply members 2a and 2b, which are introduced in an insulated manner into the metal reaction receptacle 1 and are connected through the connections 5a and 5b respectively with the two poles of a source of voltage. Thus, two zones of increased pressure are produced within the reaction receptacle 1 whereby a current of gas enters it through the nozzles of the two supply members 2a and 2b, within which receptacle a predetermined reduced pressure is maintained by means of a suction member 4. Although in such an arrangement, operated by a source of direct voltage, the one zone of increased pressure is produced at the cathode and the other one at the anode, a concentration of energy is produced in both zones and the total transformation of energy in the receptacle is divided on the two zones. This direct series connection of the two reaction zones is less advantageous than a parallel operation thereof, because the metal receptacle 1 is connected through the terminal 22 to the one pole of the source of voltage and the two supply members 2a and 2b are connected to the other pole of the source of voltage through the parallel connected terminals 5a and 5!).

It is also possible to produce more zones of increased pressure in the reaction receptacle 1, for instance 3 as shown in Figure 7. The three supply members 2a, 2b and 2c are connected either all in parallel to the same pole of a source of voltage, the other pole of which is connected to the counterelectrode 23, or the three nozzles are fed from the three phases of a three-phase supply, the star point of which is connected to the counterelectrode 23.

In the case of operation of a reaction receptacle 1 from a three-phase supply, the arrangement shown in Figure 8 is especially advantageous, wherein only one supply member 2, shown'in this case with the axis of the nozzle at right angles to the plane of the drawing, is provided but used in conjunction with three counterelectrodes 24a, 24b and 24c. The three electrodes 24a, 24b and 24c are connected through the terminals 25a, 25b, 25c to the three three-phases of the three-phase current and the supply member 2 is connected to the star point. In this way it is attained, that the zone of increased pressure, which is formed next to the nozzle mouth of the supply member is always under the action of an electric field, even when one of the phase voltages is zero.

In the arrangements hereinbefore described with reference to Figures 1 to 3 for the production of zones of higher pressure within the reaction receptacle with nonhomogeneous pressure distribution a great energy concentration of the discharge in the zone of increased pressure is effected when the pressure drop (P2-P is suitably chosen' and the reduced pressure P is outside the zone of higher pressure and when the electrode voltage is suitably chosen. This behaviour, experimentally assured, and capable of being reproduced at any time by bearing in mind the above-mentioned working data, is therefore a spacial zone which is practically released from the electrodes themselves, in which an energy transformation takes place that can be increased to high values. In the example of a reaction receptacle hereinbefore described with approximately P =20 mm. Hg and P =0.5 kg./cm. and with a nozzle of about 1 mm. internal diameter, even a direct current voltage of the order of 500 v. at the nozzle connected as a cathode produces an energy transformation within the reaction receptacle of about 1000 watts. The major part of this energy is thereby released in the zone of increased pressure and provides an energy transformation of at least 1 watt per volume element of 1 mmfi. This energy transformation, which is comparatively high for gas discharges, efiects different reactions in gaseous, vapourous or finely dispersed substances, according to their nature and composition. Apparently mainly atomic gases are produced, which in their turn act strongly on other associated reaction components that are present.

The increased pressure for carrying out reactions within the zone, and the associated reaction components provided in their immediate surroundings, are preferably combined with the gas current which enters into the reaction receptacle through the supply members and their nozzle-like openings, forming therein the zone of increased pressure. In this case, the current of gas itself may be a carrier gas which does not participate in the reaction, for instance a rare gas, which is added to the vapourous or finely dispersed solid and liquid substances to be treated. A supply member as shown, for instance, in Figure 2 is suitable for this purpose, to which the carrier gas is supplied through the backward terminal, and the' substances to be treated through the pipe connection 25. Naturally, more than one associated reaction component may be taken along by the carrier gas, for instance, a gas to be treated, and at the same time a finely dispersed substance, for instance, a metal powder which acts catalytically in the reaction. If in this case the amount of the gas to be treated is sufiiciently large to be able to carry along the other non-gaseous associated reaction components, and to produce a sufiiciently large reaction zone within the reaction receptacle, then the carrier gas which does not participate in the reaction may be entirely dispensed with. The same applies also to the case when the current of gas is a unitary gas and the only associated reaction component.

However, it is also possible, as is indicated in Figure 4, to introduce one or all the reaction associated components into the reaction zone through a separatevsupply member 2a, which is for instance desirable when the said associated reaction components come in contact with one another within the zone of increased pressure.

As already mentioned above, the speed of the current of gas flowing out of the nozzle opening is of the order of the speed of sound or higher. This causes, on the one hand, the stay of the gas within the reaction zone to be of very short durationwhich is desirable for many reactionsand, on the other hand, the reaction products to flow very rapidly out of the reaction zone. This results in a very rapid lowering of the temperature and of the volume concentration, that is to say a correspondingly reduced reaction ability of these products. Thereby, the reaction products are prevented from reverting into their starting substances, as well as from possibly further disintegrating.

Gaseous reaction products, which flow out of the zone of increased pressure into the surroundings, are removed from the receptacle through the suction members which are provided in order to maintain the desired reduced pressure in the reaction receptacle. If desired, a suitable separator for the reaction products may be provided in the suction pipe. However, if desired reaction products are produced within the reaction zone, more particularly at a definite pressure and energy level, the same may be removed therefrom directly through separate suction members, for instance by a vertical pipe 9 with a perforated annular tube acting as a suction nozzle as indicated in Figure 1. If desired, if their concentration is not suflicient, such gaseous products may be supplied again to the same reaction receptacle, in order to be subjected to the same process more than once.

If desired, the separation of certain reaction products may be etfected on walls arranged in the immediate surroundings of the reaction zone, or even project'therein. If, for instance, condensation is intended to take place on these walls, the same may be provided with hollow spaces 27 for the passage of a current of cooling means, for instance the batlle 12 shown in Figure 3. In addition to producing condensation, chemical reactions may be caused to take place on such walls, for which purpose, if desired, layers of catalyst may be provided thereon. For the purpose of easy removal of separated liquid or solid reaction products, such walls may be constituted by rotary members and be provided with a drive, so that the walls pass along stationary scraping devices;

Finally, the whole plan of one example of construction of apparatus for carrying out reactions according to the present process, will now be explained with ref erence to Figure 9. The whole of the installation is arranged with a view to carrying out reaction of a unitary gas or of a gas mixture which is under pressure in the gas flask 28. The gas to be treated flows out of the gas flask 28 through its pressure reducing valve 29 and a line regulator 30 to the supply member 2 and passes through the same into the reaction receptacle 1. The suction member 4 of the latter is connected through a separator 31 for the reaction products with a pump 32 of corresponding suction output. The pressure diagram shows the pressure characteristic of such an installation (shown in full lines). As can be seen, and as explained above in detail, within the reactionreceptacle 1, there prevails between the pressure P at the mouth of the nozzle of the supply member 2, in this case about 350 mm. Hg, and the pressure P of about 20 mm. Hg at the mouth of the suction member 4 a very non-homogeneous pressure distribution. The exponential pressure drop within the zone of increased pressure adjacent to the nozzle is also indicated.

The pressure diagram of Figure 9 shows the important differences of the above described operation of a reaction receptacle for the carrying out of reactions under the action of an electric discharge as compared with the processes hitherto known. In the case of all treatment proposals and apparatus for gases within glow discharge reaction receptacles the characteristic of the pressure, indi cated in dotted lines in the pressure diagram, shows a practically homogeneous pressure distribution within the reaction receptacle. Consequently, in the case of such an operation, no zone of marked increased pressure can be produced within which the pressure drop P :P is mostly localised. This however makes it impossible for the energy concentration of the discharge to be effected in a predetermined part of the installation.

It is to be pointed out that Figures 1 to 9 are only diagrammatic examples, and that, as regards the dimensions of the individual parts, they have been greatly exaggerated for the sake of clearer explanation.

We claim:

1. Process for producing an electric glow discharge within a reaction chamber provided with a gas suction connection and with a nozzle-like gas supply conduit, comprising introducing a gas stream into the reaction chamber by way of the gas supply conduit and subjecting the gas stream to an electric field at least at portions thereof, the supplied and withdrawn quantities ofgas being so related that a pressure drop occurs in the gas stream, at least at the electrically influenced regions, sufficient for maintaining a glow discharge.

10 2. Process for producing an electric glow discharge within a reaction chamber provided with a gas suction connection and with a nozzle-like gas supply conduit, comprising introducing a gas stream into the reaction chamber by way of the gas supply conduit and subjecting the gas streamto an electric field at leastat portions thereof, the supplied and withdrawn quantities of gas being so related that in the gas stream,v at leastin" the electrically influenced regions, between the core of the gas stream and the gas in the remainder of the reaction chamber a pressure drop of more than 2:1 iscreated and producing a glow discharge and maintaining the same in such reduced pressure zone by regulating the electric field strength.

3. Apparatus for producing an electric glow discharge, comprising a metallic chamber, a gas suction conduit connected with the chamber, a gas supply conduit connected to the chamber, said gas supply conduit terminating in a nozzle-like opening within the interior of the chamher, said opening being so shaped that a current of gas is injected into the interior 'of the chamber, in the form of a thread-like gas stream, the gas supply conduit being composed of metal and insulated with respect to the metallic wall of the chamber, said conduit being connected externally of the chamber to one pole of a source of current Whose other pole is connected with the chamber wall.

4. Apparatus for producing an electric glow discharge, comprising a metallic chamber, a gas suction conduit connected with the chamber, a gas supply conduit connected to the chamber, said gas supply conduit opening with a round nozzle-like bore in a coaxial tube whose inner diameter is greater than the diameter of the bore and debouches at its free end into the interior of the chamber, said tube being made of metal and being insulated from the metallic wall of the chamber, and being connected externallyof the chamber to one pole of a current source whose other pole is connected with the chamber wall.

5. Apparatus for producing an electric glow discharge, comprising a chamber composed at least in part of metal, a gas suction device connected to the chamber, a gas supply conduit passing through the wall of the chamber,

said gas conduit being provided with a nozzle-like open ing dobouching into the interior of the chamber and so constructed that the gas is injected by the gas conduit into the chamber inthe form of a gas stream, and a metallic part disposed downstream with reference to the gas conduit, said gas conduit being composed of metal and being insulated from said metallic part, said metallic part being connected outside of thechamber with a pole of a source of current Whose other pole is connected to the metallic gas conduit. l

6. Apparatus for producing an electric glow discharge, comprising a chamber composed at least in part of metal, a gas suction device connected to the chamber, a gas supply conduit passing through the, wall of the chamber, said gas conduit being provided with a nozzle-like opening debouching into the interior of the chamber and so constructed that the gas is injected by the gas conduit into the chamber in the form-of a gas stream, and a.

metallic part disposed downstream with reference to the gas conduit, said gas conduit being composed of metal and being insulated from said metallic part, said metallic part being connected outside of the chamber with a pole of a sourceof current whose other pole is connected to the metallic gas conduit, said metallic part being provided with an opening arranged coaxially with the gas stream, said gas suction device communicating with the interior of the chamber through said last-mentioned opening.

7. Apparatus according to claim 5, wherein the chamber is of tubular shape, the metallic gas conduit being connected at one end of the chamber, while the other end of the chamber is closed by said metallic part, the latter having an opening through which the gas suction device communicates with the interior of the chamber.

8. Apparatus for producing an electric glow discharge.

comprising a tubular metallic chamber, an insulated current connection passing through the wall of the chamber, a gas supply conduit and a gas discharge device communicating with the interior of the chamber at opposite ends thereof, the gas supply conduit debouching into the chamber through an opening which is so constructed that the gas is discharged into the chamber in the form of a gas stream which leaves the chamber at the other end thereof, the tubular chamber together with the gas supply conduit being connected with one pole of a source of current, and a counterelectrode disposed within the chamber and connected with the other pole of said source of current through said insulated current connection.

9. Process for the treatment of gaseous, vaporous and finely dispersed substances in an electrical glow discharge in a reaction chamber provided with a gas suction device and with a nozzle-like gas supply conduit, comprising injecting the substance to be treated into the chamber through the nozzle in the form of a gas stream, subjecting the gas stream within the chamber to an electric field, simultaneously withdrawing gaseous material from the chamber, so regulating the quantities of gaseous substance conducted to and withdrawn from the chamber that within at least the electrically influenced part of the gas stream there is provided a pressure drop capable of maintaining an electric glow discharge, the substance carried along in the gas stream flowing through the glow discharge zone and being capable of leaving the gas stream only along this path and regulating the speed of the gas stream to provide a predetermined time of passage of the carried-along substance in the discharge zone.

10. Process for the treatment of gaseous, vaporous and finely dispersed substances in an electrical glow discharge in a reaction chamber provided with a gas suction device and with a nozzle-like gas supply conduit comprising injecting the substance to be treated together with a carrier gas into the chamber through the nozzle in the form of a gas stream, subjecting the gas stream within the chamber to an electric field, simultaneously withdrawing gaseous material from the chamber, so regulating the quantities of gaseous substances conducted to and withdrawn from the chamber that within at least the electrically influenced part of the gas stream there is provided a pressure drop capable of maintaining an electric glow discharge, the substance carried along by the carrier gas flowing through such discharge zone and being acted on by the discharge, and thereafter leaving the gas stream together with the chemically unchanged carrier gas, and regulating the speed of the gas stream to provide a predetermined time of passage of the carried-along substance in the discharge zone.

11. Process for the treatment of gaseous, vaporous and finely dispersed substances in an electrical glow discharge in a reaction chamber provided with a gas suction device and with a nozzle-like gas supply conduit, comprising injecting the substance to be treated into the chamber through the nozzle in the form of a gas stream, subjecting the gas stream within the chamber to an electric field, so regulating the quantities of gaseous substance conducted to and withdrawn from the chamber that within at least the electrically influenced part of the gas stream there is provided a pressure drop capable of maintaining an electric glow discharge, the substance carried along in the gas stream flowing through such discharge zone and being chemically altered by the discharge, removing such chemically altered substance from Within the gas stream, and regulating the speed of the gas stream in relation to the point of removal of the chemically altered substance along the axis of the gas stream to provide a predetermined time of passage of the carried-along substance in the discharge zone.

12. irocess for the treatment of gaseous, vaporous and finely dispersed substances in an electrical glow discharge in a reaction chamber provided witha gas suction device and with a nozzle-like gas supply conduit comprising injecting a gas stream into the chamber through the nozzle, subjecting the gas stream within the chamber to an electrical field, simultaneously withdrawing gaseous material from the chamber, so regulating the quantities of gaseous substances conducted to and withdrawn from the chamber that within at least the electrically influenced part of the gas stream there is provided a pressure drop capable of maintaining an electric glow discharge, charging a substance to be treated into the gas stream, so that it is carried along by the latter through the discharge zone and can leave the gas stream only in this way, and regulating the speed of the gas stream to provide a predetermined time of passage of the carried-along substance in the discharge zone.

13. Apparatus for producing an electric glow discharge, comprising a metallic chamber, an insulated current connection passing through the wall of the chamber, a gas suction conduit connected with the chamber, a gas supply conduit connected to the chamber, said gas supply conduit terminating in a nozzle-like opening within the interior of the chamber, said opening being so shaped that a current of gas is injected into the interior of the chamber in the form of a thread-like gas stream, and an electrode positioned transversely to the axis of the nozzle and spaced apart from the mouth of the nozzle, said electrode being insulated from the chamber and being connected with an outside source of current through the said insulated current connection passing through the wall of the chamber.

14. Apparatus for producing an electric glow discharge, comprising a metallic chamber, a gas suction conduit connected With the chamber, and a plurality of gas supply conduits passing through the chamber wall, said gas supply conduits terminating in nozzle-like openings within the interior of the chamber, said openings being so shaped that currents of gas are injected into the interior of the chamber in the form of thread-like streams, the gas supply conduits being so disposed in the chamber Walls that the axes of the nozzles approximately intersect inside the chamber, said gas supply conduits being made of metal, being insulated from the chamber wall and having a connection for a source of current outside the chamber.

15. Apparatus for producing an electric glow discharge, comprising a metallic chamber, a gas suction conduit connected with the chamber, a gas supply conduit passing through the wallof the chamber, said gas suppiy conduit terminating in a nozzle-like opening within the interior of the chamber, said opening being so shaped that a current of gas is injected into the chamber in the form of a thread-like stream, and at least two electrodes arranged laterally of the axis of the nozzle and insulated from the wall of the chamber, said electrodes having terminals for connection with an outside source of current.

16. Apparatus for producing an electric glow discharge, comprising a metallic chamber, a gas suction conduit connected with the chamber, a gas supply conduit passing through the chamber wall, said gas supply conduit terminating in a nozzle-like opening within the interior of the chamber, said opening being so shaped that a current of gas is injected into the interior of the chamber in the form of a thread-like stream, said gas supply conduit being made of metal, being insulated from the wall of the chamber, and being connected outside the chamber to one pole of a source of current of which the other pole is connected to the Wall of the chamber, and an impact body spaced from the nozzle-like opening and extending transversely to the axis of said opening.

17. Apparatus for producing an electric glow discharge, comprising a metallic chamber, a gas supply conduit, said gas supply conduit terminating in a nozzlelike opening within the interior of the chamber, said opening being so shaped that a current of gas is injected into the interior of the chamber in theform of a threadlike stream, said gas supply conduit being made of metal, being insulated from the wall of the chamber and being connected outside the chamber to one pole of a source of current of which the other pole is connected to the wall of the chamber, and an impact body disposed in the chamber spaced from the nozzle-like opening and extending transversely to the axis of said opening, said impact body being provided with a suction opening and adapted to be connected with a suction pump, said impact body being connected to a gas suction conduit to withdraw gas from said chamber.

18. Apparatus for producing an electric glow discharge, comprising a metallic chamber, a gas suction conduit connected with the chamber, three gas supply conduits passing through the chamber wall and termimating in nozzle-like openings within the interior of the chamber, said openings being so shaped that currents of gas are injected into the interior of the chamber in the form of thread-like streams, the supply conduits being so disposed in the chamber wall that the axes of the nozzles approximately intersecttin the interior of the chamber, said supply conduits being made of metal, being insulated from the Wall of the chamber and having terminals outside the chamber for connection with a source 10 of three-phase current.

References Cited in the file of this patent UNITED STATES PATENTS Smyers July 11, 1939 2,582,903 Guanella et al Jan. 15, 1952 

